n. [ L. non not + plus more, further. See Plural. ] A state or condition which baffles reason or confounds judgment; insuperable difficulty; inability to proceed or decide; puzzle; quandary. [ 1913 Webster ]

Both of them are a perfect nonplus and baffle to all human understanding. South. [ 1913 Webster ]

v. t. [ imp. & p. p. Nonplused r Nonplussed; p. pr. & vb. n. Nonplusing or Nonplussing. ] To puzzle; to confound; to perplex; to cause to stop by embarrassment. [ 1913 Webster ]

He has been nonplused by Mr. Dry's desiring him to tell what it was that he endeavored to prove. Spectator. [ 1913 Webster ]